The disclosed embodiments provide a system that operates a flyback converter. During activation of a synchronous rectifier (SR) controller on a secondary side of the power converter, the system temporarily disables driving of a gate of a metal-oxide-semiconductor field-effect transistor (MOSFET) by the SR controller to enable synchronization of the SR controller to a switching frequency on a primary side of the power converter. After driving of the gate of the MOSFET by the SR controller has been disabled for a pre-specified period, the system enables driving of the gate of the MOSFET by the SR controller.
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1. A method for operating a power converter, comprising: during activation of a synchronous rectifier controller on a secondary side of the power converter, using a delay mechanism to temporarily disable driving of a gate of a metal-oxide-semiconductor field-effect transistor (MOSFET) by the synchronous rectifier controller to enable synchronization of the synchronous rectifier controller to a switching frequency on a primary side of the power converter rather than a ringing frequency; and after driving of the gate of the MOSFET by the synchronous rectifier controller has been disabled for a pre-specified period, using the delay mechanism to enable driving of the gate of the MOSFET by the synchronous rectifier controller.
A method for operating a power converter (like a flyback converter) prevents shoot-through by using a delay mechanism during synchronous rectifier (SR) controller activation on the power converter's secondary side. This mechanism temporarily stops the SR controller from driving a MOSFET gate. This ensures the SR controller synchronizes to the primary side's switching frequency, not a ringing frequency. After a set period, the delay mechanism allows the SR controller to drive the MOSFET gate again.
2. The method of claim 1 , further comprising: upon detecting an output voltage of the power converter that falls below a voltage threshold, deactivating the synchronous rectifier controller; and upon detecting a subsequent increase of the output voltage to above the voltage threshold, activating the synchronous rectifier controller.
The method from Claim 1 also includes deactivating the SR controller when the power converter's output voltage drops below a voltage threshold. The SR controller is reactivated when the output voltage subsequently rises above that threshold. This manages SR controller operation based on output voltage levels.
3. The method of claim 2 , wherein the voltage threshold is associated with a boundary between a discontinuous-conduction mode (DCM) and a continuous-conduction mode (CCM) in the power converter.
In the method described in Claims 1 and 2, the voltage threshold used to activate/deactivate the SR controller is associated with the boundary between discontinuous-conduction mode (DCM) and continuous-conduction mode (CCM) in the power converter. This boundary helps determine when to engage the synchronous rectifier.
4. The method of claim 1 , further comprising: upon detecting an aggregate current on the secondary side that falls below a current threshold, deactivating the synchronous rectifier controller; and upon detecting a subsequent increase of the aggregate current to above the current threshold, activating the synchronous rectifier controller.
The method from Claim 1 further includes deactivating the SR controller when the aggregate current on the secondary side falls below a current threshold. The SR controller is then reactivated when the aggregate current subsequently rises above that current threshold. This allows the converter to disable SR operation under light load.
5. The method of claim 4 , wherein the current threshold is associated with light-load conditions in the power converter.
In the method of Claims 1 and 4, the current threshold is associated with light-load conditions in the power converter. When the load is light enough to cause the secondary current to fall below this threshold, SR operation is disabled.
6. The method of claim 1 , wherein the pre-specified period comprises a number of cycles of gate-drive pulses on the primary side of the power converter.
In the method from Claim 1, the "pre-specified period" for disabling the MOSFET gate drive comprises a number of switching cycles of the gate-drive pulses on the primary side of the power converter. The delay is defined by the primary-side switching frequency.
7. The method of claim 1 , wherein driving of the gate of the MOSFET by the synchronous rectifier controller is disabled for the pre-specified period using an RC delay.
In the method from Claim 1, the temporary disabling of the MOSFET gate drive by the synchronous rectifier controller is implemented using an RC delay circuit for the pre-specified period. This is a hardware implementation for providing the timing delay.
8. The method of claim 1 , wherein the power converter comprises a flyback converter.
A power converter system is designed to manage electrical power distribution in a vehicle, particularly for systems requiring high reliability and efficiency. The system includes a power converter that converts input power from a primary power source into regulated output power for one or more loads. The power converter is configured to monitor and control power distribution to ensure stable operation under varying load conditions. In this configuration, the power converter is specifically implemented as a flyback converter, which is a type of switched-mode power supply that uses an inductor to store energy from the input and transfer it to the output in discrete packets. The flyback converter operates by periodically switching the inductor current on and off, allowing energy to be transferred in isolated pulses. This design is particularly useful in applications where electrical isolation between the input and output is required, such as in automotive systems where safety and reliability are critical. The system may also include additional components such as sensors, controllers, and communication interfaces to monitor and adjust power distribution dynamically. The flyback converter's efficiency and isolation capabilities make it suitable for powering sensitive electronic components in vehicles, ensuring stable and reliable operation.
9. A method for operating a power converter, comprising: upon detecting an output voltage of the power converter that falls below a voltage threshold, deactivating a synchronous rectifier controller on a secondary side of the power converter; during a subsequent activation of the synchronous rectifier controller, using a delay mechanism to temporarily disable driving of a gate of a metal-oxide-semiconductor field-effect transistor (MOSFET) by the synchronous rectifier controller to enable synchronization of the synchronous rectifier controller to a switching frequency on a primary side of the power converter rather than a ringing frequency: and after driving of the gate of the MOSFET by the synchronous rectifier controller has been disabled for a pre-specified period, using the delay mechanism to enable driving of the gate of the MOSFET by the synchronous rectifier controller.
A method for operating a power converter includes deactivating the synchronous rectifier (SR) controller on the secondary side when the output voltage falls below a threshold. Upon subsequent SR controller activation, a delay mechanism temporarily disables the SR controller from driving a MOSFET gate. This forces synchronization of the SR controller to the primary-side switching frequency instead of ringing. After a set period, the delay mechanism re-enables the SR controller to drive the MOSFET gate.
10. The method of claim 9 , further comprising: upon detecting an aggregate current on the secondary side that falls below a current threshold, deactivating the synchronous rectifier controller.
The method from Claim 9 also includes deactivating the SR controller when the aggregate current on the secondary side falls below a current threshold. This further controls when the SR is active based on current levels.
11. The method of claim 10 , further comprising: upon detecting a subsequent increase of the aggregate current to above the current threshold, activating the synchronous rectifier controller.
The method from Claims 9 and 10 includes reactivating the SR controller when the aggregate current subsequently increases to above the previously-defined current threshold. This will turn on the SR controller when the secondary current exceeds a particular value.
12. The method of claim 10 , wherein the current threshold is associated with light-load conditions in the power converter.
In the method of Claims 9 and 10, the current threshold is associated with light-load conditions in the power converter. The system uses a current threshold indicative of light load to deactivate the SR controller.
13. The method of claim 9 , further comprising: upon detecting a subsequent increase of the output voltage to above the voltage threshold, activating the synchronous rectifier controller.
The method of Claim 9 includes reactivating the synchronous rectifier controller when the output voltage subsequently increases to above the previously defined voltage threshold. This ensures the SR controller is activated after the output voltage is above the voltage threshold.
14. The method of claim 9 , wherein the pre-specified period comprises a number of cycles associated with the switching frequency of the primary side of the power converter.
In the method of Claim 9, the pre-specified period for disabling the MOSFET gate drive comprises a number of cycles associated with the switching frequency of the primary side of the power converter. The delay period is set based on the primary side switching frequency.
15. The method of claim 9 , wherein the voltage threshold is associated with a boundary between a discontinuous-conduction mode (DCM) and a continuous-conduction mode (CCM) in the power converter.
In the method of Claim 9, the voltage threshold is associated with a boundary between discontinuous-conduction mode (DCM) and continuous-conduction mode (CCM) in the power converter. The transition between DCM and CCM determines the point when the SR controller is deactivated/activated based on voltage.
16. A system for operating a power converter, comprising: a control circuit configured to activate and deactivate a synchronous rectifier controller on a secondary side of the power converter; and a delay mechanism, wherein during activation of the synchronous rectifier controller by the control circuit, the delay mechanism is configured to: temporarily disable driving of a gate of a metal-oxide-semiconductor field-effect transistor (MOSFET) by the synchronous rectifier controller to enable synchronization of the synchronous rectifier controller to a switching frequency on a primary side of the power converter rather than a ringing frequency; and after driving of the gate of the MOSFET by the synchronous rectifier controller has been disabled for a pre-specified period, enable driving of the gate of the MOSFET by the synchronous rectifier controller.
A system for operating a power converter includes a control circuit to activate and deactivate an SR controller on the secondary side, and a delay mechanism. Upon SR controller activation, the delay mechanism temporarily stops the SR controller from driving a MOSFET gate, forcing synchronization to the primary-side switching frequency. After a set period, the delay mechanism allows the SR controller to drive the MOSFET gate again.
17. The system of claim 16 , further comprising: a measurement circuit configured to measure an output voltage of the power converter, wherein activating and deactivating the synchronous rectifier controller comprises: deactivating the synchronous rectifier controller when the measured output voltage falls below a voltage threshold; and activating the synchronous rectifier controller when the measured output voltage subsequently increases to above the voltage threshold.
The system from Claim 16 also has a measurement circuit to measure the output voltage. The SR controller is deactivated when the voltage falls below a threshold and activated when the voltage subsequently rises above the threshold. SR activation/deactivation are triggered by output voltage.
18. The system of claim 17 , wherein the measurement circuit is further configured to: measure an aggregate current on the secondary side of the power converter, wherein activating and deactivating the synchronous rectifier controller comprises: deactivating the synchronous rectifier controller when the measured aggregate current falls below a current threshold; and activating the synchronous rectifier controller when the measured aggregate current subsequently increases to above the current threshold.
The system of Claim 17 includes a measurement circuit to measure aggregate secondary-side current. The SR controller is deactivated when the current falls below a threshold and activated when the current subsequently rises above the threshold. SR activation/deactivation are also triggered by secondary current levels.
19. The system of claim 18 , wherein the current threshold is associated with light-load conditions in the power converter.
In the system of Claim 18, the current threshold is associated with light-load conditions. The current threshold is set to trigger SR deactivation when the power converter is lightly loaded.
20. The system of claim 17 , wherein the voltage threshold is associated with a boundary between a discontinuous-conduction mode (DCM) and a continuous-conduction mode (CCM) in the power converter.
In the system of Claim 17, the voltage threshold is associated with the boundary between discontinuous-conduction mode (DCM) and continuous-conduction mode (CCM). SR activation/deactivation are also triggered by whether the power converter is in DCM or CCM based on the measured output voltage.
21. The system of claim 16 , wherein the pre-specified period comprises a number of cycles associated with the switching frequency of the primary side of the power converter.
In the system from Claim 16, the "pre-specified period" is a number of cycles associated with the primary-side switching frequency. The delay is configured based on a number of cycles of the primary-side switching waveform.
22. A non-transitory computer-readable storage medium storing instructions that when executed by a controller cause the controller to perform a method for operating a power converter, the method comprising: during activation of a synchronous rectifier controller on a secondary side of the power converter, using a delay mechanism to temporarily disable driving of a gate of a metal-oxide-semiconductor field-effect transistor (MOSFET) by the synchronous rectifier controller to enable synchronization of the synchronous rectifier controller to a switching frequency on a primary side of the power converter; and after driving of the gate of the MOSFET by the synchronous rectifier controller has been disabled for a pre-specified period, using the delay mechanism to enable driving of the gate of the MOSFET by the synchronous rectifier controller.
A computer-readable medium stores instructions to operate a power converter. Upon SR controller activation, a delay mechanism temporarily stops the SR controller from driving a MOSFET gate, forcing synchronization to the primary-side switching frequency. After a set period, the delay mechanism allows the SR controller to drive the MOSFET gate again.
23. The non-transitory computer-readable storage medium of claim 22 , the method further comprising: upon detecting an aggregate current on the secondary side that falls below a current threshold, deactivating the synchronous rectifier controller; and upon detecting a subsequent increase of the aggregate current to above the current threshold, activating the synchronous rectifier controller.
The computer-readable medium of Claim 22 also includes instructions to deactivate the SR controller when the secondary-side current falls below a threshold and activate it when the current subsequently rises above the threshold. This is an additional condition that can be programmed.
24. The non-transitory computer-readable storage medium of claim 23 , wherein the current threshold is associated with light-load conditions in the power converter.
In the computer-readable medium of Claim 23, the current threshold is associated with light-load conditions. The software uses a specific current threshold that's determined to be indicative of the power converter operating under light load conditions.
25. The non-transitory computer-readable storage medium of claim 22 , the method further comprising: upon detecting an output voltage of the power converter that falls below a voltage threshold, deactivating the synchronous rectifier controller; and upon detecting a subsequent increase of the output voltage to above the voltage threshold, activating the synchronous rectifier controller.
The computer-readable medium of Claim 22 also includes instructions to deactivate the SR controller when the output voltage falls below a threshold and activate it when the voltage subsequently rises above the threshold. This gives another condition for controlling SR activation.
26. The non-transitory computer-readable storage medium of claim 25 , wherein the voltage threshold is associated with a boundary between a discontinuous-conduction mode (DCM) and a continuous-conduction mode (CCM) in the power converter.
In the computer-readable medium of Claim 25, the voltage threshold is associated with the boundary between discontinuous-conduction mode (DCM) and continuous-conduction mode (CCM). The programmed software uses the voltage value at the DCM/CCM boundary as the threshold.
27. The non-transitory computer-readable storage medium of claim 22 , wherein the pre-specified period comprises a number of cycles of the gate-drive pulses on the primary side of the power converter.
In the computer-readable medium of Claim 22, the "pre-specified period" is a number of cycles of the primary-side gate-drive pulses. The programmed delay is set according to the primary side gate drive pulses.
28. The non-transitory computer-readable storage medium of claim 22 , wherein disabling driving of the gate of the MOSFET by the synchronous rectifier controller comprises: blanking a gate-drive signal of the synchronous rectifier controller during the pre-specified period.
In the computer-readable medium of Claim 22, disabling the MOSFET gate drive involves blanking the SR controller's gate-drive signal during the pre-specified period. The program effectively turns off or blanks out the gate drive signal during the delay period.
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December 30, 2015
September 19, 2017
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